Re: [PATCH 3/4] spi: dw: Convert to using the Bitfield access macros

From: Serge Semin
Date: Fri Nov 12 2021 - 16:43:56 EST

On Fri, Nov 12, 2021 at 11:23:54PM +0200, Andy Shevchenko wrote:
> On Fri, Nov 12, 2021 at 10:51 PM Serge Semin
> <Sergey.Semin@xxxxxxxxxxxxxxxxxxxx> wrote:
> >
> > The driver has been using the offset/bitwise-shift-based approach for the
> > CSR fields R/W operations since it was merged into the kernel. It can be
> > simplified by using the macros defined in the linux/bitfield.h and
> > linux/bit.h header files like BIT(), GENMASK(), FIELD_PREP(), FIELD_GET(),
> > etc where it is required, for instance in the cached cr0 preparation
> > method. Thus in order to have the FIELD_*()-macros utilized we just need
> > to convert the macros with the CSR-fields offsets to the masks with the
> > corresponding registers fields definition. That's where the GENMASK() and
> > BIT() macros come in handy. After that the masks can be used in the
> > FIELD_*()-macros where it's appropriate.
> >
> > We also need to convert the macros with the CRS-bit flags using the manual
> > bitwise shift operations (x << y) to using the BIT() macro. Thus we'll
> > have a more coherent set of the CSR-related macros.
> >
> > Signed-off-by: Serge Semin <Sergey.Semin@xxxxxxxxxxxxxxxxxxxx>
> > ---
> > drivers/spi/spi-dw-core.c | 31 +++++++++++--------
> > drivers/spi/spi-dw.h | 64 +++++++++++++++++++--------------------
> > 2 files changed, 50 insertions(+), 45 deletions(-)
> >
> > diff --git a/drivers/spi/spi-dw-core.c b/drivers/spi/spi-dw-core.c
> > index 4d91ffb5c0d8..b4cbcd38eaba 100644
> > --- a/drivers/spi/spi-dw-core.c
> > +++ b/drivers/spi/spi-dw-core.c
> > @@ -5,6 +5,7 @@
> > * Copyright (c) 2009, Intel Corporation.
> > */
> >
> > +#include <linux/bitfield.h>
> > #include <linux/dma-mapping.h>
> > #include <linux/interrupt.h>
> > #include <linux/module.h>
> > @@ -254,7 +255,7 @@ static irqreturn_t dw_spi_irq(int irq, void *dev_id)
> > {
> > struct spi_controller *master = dev_id;
> > struct dw_spi *dws = spi_controller_get_devdata(master);
> > - u16 irq_status = dw_readl(dws, DW_SPI_ISR) & 0x3f;
> > + u16 irq_status = dw_readl(dws, DW_SPI_ISR) & DW_SPI_INT_MASK;
> >
> > if (!irq_status)
> > return IRQ_NONE;
> > @@ -273,32 +274,38 @@ static u32 dw_spi_prepare_cr0(struct dw_spi *dws, struct spi_device *spi)
> >
> > if (!(dws->caps & DW_SPI_CAP_DWC_HSSI)) {
> > /* CTRLR0[ 5: 4] Frame Format */
> > - cr0 |= DW_SPI_CTRLR0_FRF_MOTO_SPI << DW_PSSI_CTRLR0_FRF_OFFSET;
> > + cr0 |= FIELD_PREP(DW_PSSI_CTRLR0_FRF_MASK, DW_SPI_CTRLR0_FRF_MOTO_SPI);
> >
> > /*
> > * SPI mode (SCPOL|SCPH)
> > * CTRLR0[ 6] Serial Clock Phase
> > * CTRLR0[ 7] Serial Clock Polarity
> > */
> > - cr0 |= ((spi->mode & SPI_CPOL) ? 1 : 0) << DW_PSSI_CTRLR0_SCOL_OFFSET;
> > - cr0 |= ((spi->mode & SPI_CPHA) ? 1 : 0) << DW_PSSI_CTRLR0_SCPH_OFFSET;
> > + if (spi->mode & SPI_CPOL)
> > + cr0 |= DW_PSSI_CTRLR0_SCPOL;
> > + if (spi->mode & SPI_CPHA)
> > + cr0 |= DW_PSSI_CTRLR0_SCPHA;
> >
> > /* CTRLR0[11] Shift Register Loop */
> > - cr0 |= ((spi->mode & SPI_LOOP) ? 1 : 0) << DW_PSSI_CTRLR0_SRL_OFFSET;
> > + if (spi->mode & SPI_LOOP)
> > + cr0 |= DW_PSSI_CTRLR0_SRL;
> > } else {
> > /* CTRLR0[ 7: 6] Frame Format */
> > - cr0 |= DW_SPI_CTRLR0_FRF_MOTO_SPI << DW_HSSI_CTRLR0_FRF_OFFSET;
> > + cr0 |= FIELD_PREP(DW_HSSI_CTRLR0_FRF_MASK, DW_SPI_CTRLR0_FRF_MOTO_SPI);
> >
> > /*
> > * SPI mode (SCPOL|SCPH)
> > * CTRLR0[ 8] Serial Clock Phase
> > * CTRLR0[ 9] Serial Clock Polarity
> > */
> > - cr0 |= ((spi->mode & SPI_CPOL) ? 1 : 0) << DW_HSSI_CTRLR0_SCPOL_OFFSET;
> > - cr0 |= ((spi->mode & SPI_CPHA) ? 1 : 0) << DW_HSSI_CTRLR0_SCPH_OFFSET;
> > + if (spi->mode & SPI_CPOL)
> > + cr0 |= DW_HSSI_CTRLR0_SCPOL;
> > + if (spi->mode & SPI_CPHA)
> > + cr0 |= DW_HSSI_CTRLR0_SCPHA;
> >
> > /* CTRLR0[13] Shift Register Loop */
> > - cr0 |= ((spi->mode & SPI_LOOP) ? 1 : 0) << DW_HSSI_CTRLR0_SRL_OFFSET;
> > + if (spi->mode & SPI_LOOP)
> > + cr0 |= DW_HSSI_CTRLR0_SRL;
> >
> > if (dws->caps & DW_SPI_CAP_KEEMBAY_MST)
> > cr0 |= DW_HSSI_CTRLR0_KEEMBAY_MST;
> > @@ -320,10 +327,10 @@ void dw_spi_update_config(struct dw_spi *dws, struct spi_device *spi,
> >
> > if (!(dws->caps & DW_SPI_CAP_DWC_HSSI))
> > /* CTRLR0[ 9:8] Transfer Mode */
> > - cr0 |= cfg->tmode << DW_PSSI_CTRLR0_TMOD_OFFSET;
> > + cr0 |= FIELD_PREP(DW_PSSI_CTRLR0_TMOD_MASK, cfg->tmode);
> > else
> > /* CTRLR0[11:10] Transfer Mode */
> > - cr0 |= cfg->tmode << DW_HSSI_CTRLR0_TMOD_OFFSET;
> > + cr0 |= FIELD_PREP(DW_HSSI_CTRLR0_TMOD_MASK, cfg->tmode);
> >
> > dw_writel(dws, DW_SPI_CTRLR0, cr0);
> >
> > @@ -850,7 +857,7 @@ static void dw_spi_hw_init(struct device *dev, struct dw_spi *dws)
> >
> > if (!(cr0 & DW_PSSI_CTRLR0_DFS_MASK)) {
> > dws->caps |= DW_SPI_CAP_DFS32;
> > - dws->dfs_offset = DW_PSSI_CTRLR0_DFS32_OFFSET;
> > + dws->dfs_offset = __bf_shf(DW_PSSI_CTRLR0_DFS32_MASK);
> > dev_dbg(dev, "Detected 32-bits max data frame size\n");
> > }
> > } else {
> > diff --git a/drivers/spi/spi-dw.h b/drivers/spi/spi-dw.h
> > index 893b78c43a50..634085eadad1 100644
> > --- a/drivers/spi/spi-dw.h
> > +++ b/drivers/spi/spi-dw.h
>

> Haven't deeply checked this, but below changes require to have bits.h
> to be included.
> Please, double check this is included already.

Checked. It's there. The bits.h file inclusion has been added
in commit cc760f3143f5 ("spi: dw: Convert CS-override to DW SPI
capabilities"). Thanks for pointing this out anyway.

-Sergey

>
> > @@ -41,39 +41,36 @@
> > #define DW_SPI_CS_OVERRIDE 0xf4
> >
> > /* Bit fields in CTRLR0 (DWC APB SSI) */
> > -#define DW_PSSI_CTRLR0_DFS_OFFSET 0
> > #define DW_PSSI_CTRLR0_DFS_MASK GENMASK(3, 0)
> > -#define DW_PSSI_CTRLR0_DFS32_OFFSET 16
> > +#define DW_PSSI_CTRLR0_DFS32_MASK GENMASK(20, 16)
> >
> > -#define DW_PSSI_CTRLR0_FRF_OFFSET 4
> > +#define DW_PSSI_CTRLR0_FRF_MASK GENMASK(5, 4)
> > #define DW_SPI_CTRLR0_FRF_MOTO_SPI 0x0
> > #define DW_SPI_CTRLR0_FRF_TI_SSP 0x1
> > #define DW_SPI_CTRLR0_FRF_NS_MICROWIRE 0x2
> > #define DW_SPI_CTRLR0_FRF_RESV 0x3
> >
> > -#define DW_PSSI_CTRLR0_MODE_OFFSET 6
> > -#define DW_PSSI_CTRLR0_SCPH_OFFSET 6
> > -#define DW_PSSI_CTRLR0_SCOL_OFFSET 7
> > +#define DW_PSSI_CTRLR0_MODE_MASK GENMASK(7, 6)
> > +#define DW_PSSI_CTRLR0_SCPHA BIT(6)
> > +#define DW_PSSI_CTRLR0_SCPOL BIT(7)
> >
> > -#define DW_PSSI_CTRLR0_TMOD_OFFSET 8
> > -#define DW_PSSI_CTRLR0_TMOD_MASK (0x3 << DW_PSSI_CTRLR0_TMOD_OFFSET)
> > +#define DW_PSSI_CTRLR0_TMOD_MASK GENMASK(9, 8)
> > #define DW_SPI_CTRLR0_TMOD_TR 0x0 /* xmit & recv */
> > #define DW_SPI_CTRLR0_TMOD_TO 0x1 /* xmit only */
> > #define DW_SPI_CTRLR0_TMOD_RO 0x2 /* recv only */
> > #define DW_SPI_CTRLR0_TMOD_EPROMREAD 0x3 /* eeprom read mode */
> >
> > -#define DW_PSSI_CTRLR0_SLVOE_OFFSET 10
> > -#define DW_PSSI_CTRLR0_SRL_OFFSET 11
> > -#define DW_PSSI_CTRLR0_CFS_OFFSET 12
> > +#define DW_PSSI_CTRLR0_SLV_OE BIT(10)
> > +#define DW_PSSI_CTRLR0_SRL BIT(11)
> > +#define DW_PSSI_CTRLR0_CFS BIT(12)
> >
> > /* Bit fields in CTRLR0 (DWC SSI with AHB interface) */
> > -#define DW_HSSI_CTRLR0_SRL_OFFSET 13
> > -#define DW_HSSI_CTRLR0_TMOD_OFFSET 10
> > +#define DW_HSSI_CTRLR0_DFS_MASK GENMASK(4, 0)
> > +#define DW_HSSI_CTRLR0_FRF_MASK GENMASK(7, 6)
> > +#define DW_HSSI_CTRLR0_SCPHA BIT(8)
> > +#define DW_HSSI_CTRLR0_SCPOL BIT(9)
> > #define DW_HSSI_CTRLR0_TMOD_MASK GENMASK(11, 10)
> > -#define DW_HSSI_CTRLR0_SCPOL_OFFSET 9
> > -#define DW_HSSI_CTRLR0_SCPH_OFFSET 8
> > -#define DW_HSSI_CTRLR0_FRF_OFFSET 6
> > -#define DW_HSSI_CTRLR0_DFS_OFFSET 0
> > +#define DW_HSSI_CTRLR0_SRL BIT(13)
> >
> > /*
> > * For Keem Bay, CTRLR0[31] is used to select controller mode.
> > @@ -86,26 +83,27 @@
> > #define DW_SPI_NDF_MASK GENMASK(15, 0)
> >
> > /* Bit fields in SR, 7 bits */
> > -#define DW_SPI_SR_MASK 0x7f /* cover 7 bits */
> > -#define DW_SPI_SR_BUSY (1 << 0)
> > -#define DW_SPI_SR_TF_NOT_FULL (1 << 1)
> > -#define DW_SPI_SR_TF_EMPT (1 << 2)
> > -#define DW_SPI_SR_RF_NOT_EMPT (1 << 3)
> > -#define DW_SPI_SR_RF_FULL (1 << 4)
> > -#define DW_SPI_SR_TX_ERR (1 << 5)
> > -#define DW_SPI_SR_DCOL (1 << 6)
> > +#define DW_SPI_SR_MASK GENMASK(6, 0)
> > +#define DW_SPI_SR_BUSY BIT(0)
> > +#define DW_SPI_SR_TF_NOT_FULL BIT(1)
> > +#define DW_SPI_SR_TF_EMPT BIT(2)
> > +#define DW_SPI_SR_RF_NOT_EMPT BIT(3)
> > +#define DW_SPI_SR_RF_FULL BIT(4)
> > +#define DW_SPI_SR_TX_ERR BIT(5)
> > +#define DW_SPI_SR_DCOL BIT(6)
> >
> > /* Bit fields in ISR, IMR, RISR, 7 bits */
> > -#define DW_SPI_INT_TXEI (1 << 0)
> > -#define DW_SPI_INT_TXOI (1 << 1)
> > -#define DW_SPI_INT_RXUI (1 << 2)
> > -#define DW_SPI_INT_RXOI (1 << 3)
> > -#define DW_SPI_INT_RXFI (1 << 4)
> > -#define DW_SPI_INT_MSTI (1 << 5)
> > +#define DW_SPI_INT_MASK GENMASK(5, 0)
> > +#define DW_SPI_INT_TXEI BIT(0)
> > +#define DW_SPI_INT_TXOI BIT(1)
> > +#define DW_SPI_INT_RXUI BIT(2)
> > +#define DW_SPI_INT_RXOI BIT(3)
> > +#define DW_SPI_INT_RXFI BIT(4)
> > +#define DW_SPI_INT_MSTI BIT(5)
> >
> > /* Bit fields in DMACR */
> > -#define DW_SPI_DMACR_RDMAE (1 << 0)
> > -#define DW_SPI_DMACR_TDMAE (1 << 1)
> > +#define DW_SPI_DMACR_RDMAE BIT(0)
> > +#define DW_SPI_DMACR_TDMAE BIT(1)
> >
> > /* Mem/DMA operations helpers */
> > #define DW_SPI_WAIT_RETRIES 5
> > --
> > 2.33.0
> >
>
>
> --
> With Best Regards,
> Andy Shevchenko